Mount base wobble

[Guest]

I have to take the scope in and out on each session and I had a 3x3 square of 2ft concrete slabs in my vegetable plot to stand the mount on. I soon realised though that even thought the slabs seem pretty stable they do move. I usually work on my laptop on a camping table next to the scope. I have to sit still and make sure I keep my feet away from the slabs the mount is on. The HEQ5 mount takes up a 2x2 section of the slabs and my camp table and seat sit along side on the remaining slabs.

So, I decided to do something about it by laying a square of concrete next to the slabs with a gap between the concrete and the slabs where my camp table is. The concrete slab is 4 feet square and 3 inches deep and laid on hardcore. I thought nothing will move this but I was surprised to see that it did. If I walked on the concrete area I could see the disturbance in the PHD2 guide graph - like a seismograph.  I suppose on the scale of things it wasn't such a big disturbance.  It normally guides within +/- 1 arc second. The disturbances went +/- 7 arc second and PHD2 quickly controls it.

It's still much better than it was and providing I don't migrate onto the concrete slab it'll be ok and I can work with that. I was just surprised at how sensitive it was.

[PhilPassmore]

I observe from a raised deck, which being flexible wood was somewhat 'sub-optimal' in the vibration department (ie, stand VERY still when observing). So I used a bit of plastic drainpipe (150mm) as a former, cut into the concrete yard and hammered in reinforcing rods, ran a scaffold tube up inside the former, and filled it with concrete. This brought me up to deck level, and I set threaded rods into the top of the concrete, and use those to bolt a homemade pier onto, that is completely isolated from the deck. 

[Guest]

Neat!

[Xoc1]

The Isolation Pillar reminds me of the sort of things we had to do to use record players in Nighclubs. Find something solid & build an isolated support to the record deck.

 

As regards the vibration transfer I think distance is the key to minimise the disturbance. I use some 5 metre leads which seem to be OK for USB and apart from focussing I get in the garden cabin for comfy camera sessions.

So one of my priority projects is a motorised focusser so I can keep my distance.

 

[Merlin]

Vibration can be a problem in many ways. When my daughter was a child, she was in the habit, as many children are, of jumping from last few steps in the staircase onto the floor.

Alas, this habit ruined several LPs by making the stylus on the record player in the lounge jump across the vinyl, leaving pits and scratches on its surface.

[paraman]

12 hours ago, Merlin said:

Vibration can be a problem in many ways. When my daughter was a child, she was in the habit, as many children are, of jumping from last few steps in the staircase onto the floor.

Alas, this habit ruined several LPs by making the stylus on the record player in the lounge jump across the vinyl, leaving pits and scratches on its surface.

Back in the day When I could afford decent hifi my wife did a double whammy on me.  She cleaned my pride and joy Linn sondek lp12 with silicon furniture polish, write off one expensive drive belt. New belt purchased and fitted only to discover even more expensive moving coil cartridge was minus a stylus, the light of my life cleaned a bit of lint "off the end" with a duster.  The new cartridge set me back £253 in 1983. Banned for life from even so much as breathing on it.